Exclude external media from service worker

[bravokiloecho]

When I visit a page on my app that displays images from Instagram, it looks like the service worker is trying to cache these (see image at bottom).

I've tried to exlude these files by adding a workbox config to my next.config.js like this:

const withPlugins = require('next-compose-plugins')
const withOffline = require('next-offline')

// Next phase vars
const {
  PHASE_DEVELOPMENT_SERVER,
} = require('next/constants')

const nextConfig = {
  // Customise service worker
  workboxOpts: {
    exclude: [/^https:\/\/scontent\.xx\.fbcdn\.net.+/],
  },
}

module.exports = withPlugins([
  // load and apply a plugin only during development server phase
  [withOffline, ['!', PHASE_DEVELOPMENT_SERVER]],
], nextConfig)

But this doesn't seem to have any effect.

Is there a better way of doing this? I'm aware that I'm not totally familiar with all these things.